The invention refers to a vehicle door latch with a locking mechanism, at least one operating lever for the locking mechanism and a motor drive for opening the locking mechanism. As usual, the locking mechanism mainly consists of a catch and a pawl.
Such vehicle door latches are adequately known and are used where such a latch is to be opened electrically. As such a motor drive generally contains an electric motor. The described electric opening is, for instance but not exclusively, initiated by a so-called “keyless entry” or “keyless go” operation. In this case, an upstream wireless authorization check is carried out on an operator seeking to gain access, which after a positive check actuates the motor drive for opening the locking mechanism, so that immediately afterwards, a vehicle door can be opened and/or released. This may also be motor-driven or manual process.
At the same time, it is also possible to operate an internal door handle or external door handle, with this action being detectable by a switch assigned to the respective handle. Depending on the functional position of the vehicle door latch (e.g. unlocked, locked or double locked), the obtained switching signal is converted into a respective execution signal for the motor drive.
Generally, the motor drive in question only arranges the opening of the respective locking mechanism. This means that, the mechanism must first be moved to the unlocked state if it is not already in this state. Generally, the motor drive can also be used for first unlocking the vehicle door latch and then opening the locking mechanism.
Prior art has already disclosed successful attempts of developing a vehicle door latch in such a way that its opening is guaranteed in any event. The generic WO 03/018939 A1 suggests, for instance that the motor drive acts indirectly on the operating lever or actuating lever via an intermediate energy-saving device.
A solution according to also a generic EP 1 091 061 A2 contains an already more complex mechanical system. In this system, the drive disc of the motor drive contains a driving pin, arranged with a stop on a blocking lever, arranged separately from the pawl of the locking mechanism. This blocking lever is moved along by the pawl, during its displacement, into a position releasing the catch, its blocking position. This is mechanically more complex and more expensive.
A similar system is shown in the generic door latch of EP 1 085 148 A2. In this case, too, a blocking lever is provided in addition to the opening lever with both being arranged to rotate around a common axis.—The invention aims to provide a solution for this problem.